The purpose of this 4 year study entitled "Drug Use, Housing Access, Stability and HIV Risk among Low- Income Urban Residents" is to explore the relationship between structural factors of housing (access to housing subsidies and programs, status and stability) and HIV risk among drug users. The proposed project will test hypotheses that drug users have less access to federal, state and local housing subsidies and programs than low-income non-drug users, and that housing instability increases drug users'HIV risk. The specific aims of the proposed study include the following: 1) To compare low-income drug users'and low- income non-drug users'access to housing and social services, and their housing stability over time in the two study towns controlling for personal characteristics;2) To examine the mediating relationship of housing access between drug use and housing status/stability;3) To examine the relationship between housing status and HIV risk for drug using and non-drug using low-income residents;and 4) To explore differences in program requirements and supportive services offered by different supportive housing programs and their impact on applicants'access to supportive housing programs, maintenance of housing stability, and drug use and HIV risk behaviors. To explore these 4 aims, we will conduct longitudinal surveys with a cohort of 300 drug using and 150 non-drug using low-income residents of Hartford and East Hartford at baseline, 6 and 12 months. Low-income residents of the two communities will be recruited through targeted sampling, using an instrument developed in an exploratory qualitative study (R21 DA 018607). We will over-recruit 100 residents of supportive housing programs as part of this larger sample by directly recruiting at the agencies that provide supportive housing in order to ensure sufficient sample size. The survey includes detailed measures of housing status and stability, access to housing subsidies, supportive housing, welfare and health benefits, neighborhood characteristics, health and mental health status, drug use and HIV risk behaviors. In addition, we will explore housing access at the neighborhood level (number of rental housing units, vacancy rates, number of supportive and low-income housing, number of shelters) by mapping secondary housing data and modeling housing availability using geospatial analysis. Risk will also be assessed at the neighborhood level by mapping and geospatial modeling of drug related and violent arrests, and locations of abandoned buildings in relation to participants'residences or, if homeless, the location/s where they most frequently spend the night. In order to explore more fully the differences in philosophy and program requirements of different supportive housing programs as part of aim 4, we will conduct in-depth interviews with service providers in each of the 5 supportive housing programs in the study towns. This exploratory aim will allow us to develop measures and relationships to more fully evaluate different supportive housing programs in a subsequent study. Information from this project will allow identification of structural conditions that limit drug users'access to housing and contribute to their housing instability. Such information will contribute significantly to the development of interventions to reduce some of the root causes of drug users'vulnerability to HIV infection, including developing new housing alternatives for active drug users at high risk for homelessness, HIV prevention interventions that address contextual risk factors of homeless drug users, and policy recommendations to improve drug users'access to housing and overall health.